These days, apparatus and technology are developed in which touch operation is enabled on wall surfaces, the upper surfaces of desks, whiteboards, etc. Furthermore, the apparatus can cooperate with a projector etc. to make any object surface a virtual touch display. Conventionally, it has been necessary to attach a large-sized sensor for touch detection to an object surface, and there have been limitations to usable object surfaces. These days, a system is proposed in which operation on any object surface is detected by using a dedicated device such as an electronic pen that emits infrared light. However, in such an apparatus, operations with an indicator such as a finger and a pointer, are not detected. In this regard, an apparatus is proposed that senses an object surface with a sensor such as a camera placed in a distant position and detects an indicator such as a finger and a pointer. However, in such an apparatus, detection of an indicator is inaccurate as compared to systems using a dedicated device. Furthermore, misalignment may occur between touch coordinate and position of the indicator. It makes operation unstable.